Not applicable.
This invention relates to a method of producing high quality interlaced image plots having exceptionally sharp, smooth type and line edges for conveying various desired visual effects when the image plots are printed and subsequently viewed through a properly positioned and aligned sheet of a lenticular lens material; and more particularly, to a process which substantially eliminates xe2x80x9cghostingxe2x80x9d effects which otherwise can occur.
In U.S. patent application Ser. No. 08/862,028 a method is described for producing an image plot of interlaced images (including both graphic and textual images) which is mapped or registered to a particular lenticular lens material. That is, a digital file is prepared which is specific to the lens material taking into effect the lenticules per inch (LPI) and other characteristics of the material. The resulting printed materials are then used for advertisement, promotional, security and packaging materials and incorporate a variety of visual effects as described in the referenced application. As is well-known in the art, these effects result from changing the angle at which the printed lenticular material is viewed.
While the process described in the referenced application represents a marked improvement over prior prepress techniques, a problem which still needs to be addressed is one referred to as xe2x80x9cghosting.xe2x80x9d As the name implies, ghosting is a visual effect in which an image being viewed appears to also include elements of another image. A typical example of ghosting is the halo effect created when one looks a white circle surrounded by a black background. Oftentimes there appears to be an overlap of the circle into the background. In a sheet of lenticular lens material, light impinging on the lenticules is reflected throughout the lenticular material. Given the convex shape of the lenticules, the light reflects at different angles. This means that even though only one segment of the printed image is viewed for a given viewing angle, the light reflects off other segments of the image so that they, too, may appear to some extent to the viewer.
In the method described in the referenced application, graphic images (continuous tone) and lettering or other uniform color segments (linework) are separately processed and the results combined into composite digital file. Ghosting effects occur with both types of images and eliminating this effect will improve the overall quality of the printed result.
Among the several objects of the present invention may be noted the provision of a method of performing a prepress operation by which a plurality of graphic and textual images are combined to produce a high resolution film plot of interlaced continuous tone and linework images which is mapped to a particular lenticular lens material;
the provision of a process in which ghosting effects are substantially eliminated so to enhance the quality of the printed product;
the provision of such a process to produce in which ghosting effects occurring in either or both linework or continuous tone images are eliminated;
the provision of such a process in which an average color value is computed for a predetermined number of pixels adjacent to a selected pixel in the resultant interlaced linework or continuous tone image plot, the process beginning at the first address in the image plot and being carried successively through to the last address in the plot;
the provision of such a process in which each color (cyan C, magenta M, yellow Y, and black K) used in the printing process is subject to being enhanced or diminished;
the provision of such a process in which the color value for the color at a particular address is compared to the average color value across the predetermined number of adjacent pixels;
the provision of such a process in which the color value for the particular address is enhanced if it exceeds the computed average value, is lessened if it is less than the average value, or left alone if it equals the average value; and,
the provision of such a process in which the degree to which a color value is enhanced or lessened is predetermined value based upon characteristics of the lenticular lens material on which the composite image will be printed.
In accordance with the invention, generally stated, a process for producing a composite image from a plurality of images, the composite image being printed on lenticular lens material. The composite image is a digitized image in which each pixel has a unique address and an accompanying digital value representing a particular color for the that pixel location and the percentage of that color. The composite image is comprised of an interlaced linework image and an interlaced continuous tone image. After each interlaced image is formed, the process comprises computing an average color value of a predetermined number of adjacent pixel addresses on each side of a particular pixel address. The color value at the particular address is then compared with the computed average value. If the color value is greater than the average, the color value is enhanced a predetermined amount and a new color value is stored at that pixel address. If the color value is less than the average, the color value is diminished and the new color value is stored at the pixel address. If the color value equals the average, the color value is not adjusted. The degree of color enhancement or diminishment is a function of the lens material on which the composite image is printed. The process substantially eliminates ghosting effects which might otherwise show-up when the printed lens material is viewed. Other objects and features will be in part apparent and in part pointed out hereinafter.